The Advantages of Heat Treating CNC Machined Parts

Updated for December 2024

When you need hard and strong parts for aerospace and other high-stakes applications, heat treating is a great way to save money while meeting demanding specifications. 

You don’t have to resort to an expensive metal like titanium to get the hardness and strength you’re looking for. Focused on Machining can help you select an alternate material that, post-heat treating, will have all the properties your part requires. 

Best of all, we remain true to our promise of getting you high-quality parts when YOU need them, turning around heat-treating jobs in a few short weeks. 

Why Use Heat Treated Steel or Aerospace Alloys Instead of Titanium? 

Heat-treated steel or aerospace alloys offer significant advantages over more expensive materials such as titanium, Inconel, and Monel, both in terms of cost and performance. While these premium materials can be prohibitively expensive, heat-treated options provide a cost-effective solution without sacrificing strength or hardness.

For example, the 4340 aerospace alloy, developed specifically for aircraft components, can achieve a remarkable 260,000 psi in strength after heat treatment. This makes it even stronger than titanium in many cases, providing the necessary durability and resilience for high-stress applications. Additionally, when heat treated, steel and aerospace alloys offer substantial savings—typically ranging from $2 to $5 per pound plus a reasonable lot fee of $175-$300—compared to the volatile pricing of materials like titanium post-Covid.

Not only does this approach lower material costs, but it also results in a part that can outperform more expensive alternatives in terms of strength and hardness. For industries where both performance and budget are critical, heat-treated steel or aerospace alloys represent an optimal choice.

Challenges of Heat Treating CNC Machined Parts

Many machine shops shy away from quoting jobs that require heat treating due to the complexities and risks involved in the process. It's easy to make mistakes, such as over- or under-heat treating a part, which can lead to issues with strength or brittleness. Under-heat treating can result in a part that's not strong enough for its intended application, while over-heat treating can cause the material to become too brittle, compromising its integrity.

At our Colorado machine shop, we take a different approach by using the vacuum method for heat treating. We prefer this method because it offers several distinct advantages:

  • Aesthetic Appeal: Vacuum heat treating minimizes the risk of parts coming out burnt, ensuring that the finished product is visually clean and professional-looking.

  • Consistency: The vacuum method delivers more consistent results, reducing the chance of contaminants or other materials being impregnated into the parts, which can sometimes happen with traditional heat treating methods.

  • Readiness for Further Processing: Parts treated using the vacuum method are ready for additional forming or machining without discoloration or the need for cleaning, streamlining the production process.

By using the vacuum method, we can offer a higher level of precision and quality control, ensuring that heat-treated parts meet the exacting standards required for demanding applications.

Why Rely on Focused on Machining for Heat Treating CNC Machined Parts?

Any machine shop can offer heat treating, but that doesn’t mean they’re doing it right. Your best bet is to rely on an AS9100 machine shop like Focused on Machining that will never just place a part in the oven and hope for the best. We manage heat treating through our expert vendor network, delivering high-quality parts with fast turnaround times. Here’s what we offer our customers: 

  • Tight tolerance furnaces

  • Material testing and analysis 

  • Certified to AMS (Aerospace Material Specifications) standards

  • ISO Certified 

  • NADCAP certified

Heat Treated Pins for an Aerospace Customer

We recently made these heat-treated pins for one of our aerospace machining customers. These pins are critical components as they hold together the elevators that control an aircraft's up-and-down movement. Given the importance of this part, it was essential to meet specific performance criteria: the pins needed to be stronger than the shaft they support but still designed to break away if something goes wrong.

Heat-treated 4340 alloy steel was the perfect material for this part, providing the strength the customer required while also saving them money. We turned this job around in a quick 2.5 weeks, although the heat treating alone took about 5 days! 

Don’t rely on just any precision machine shop to heat treat your CNC machined parts. Let Focused on Machining own all the behind-the-scenes work for you. We’re a one-stop shop—no matter what services you need, we will manage your full manufacturing process and deliver you a completed part. For repeat production customers, we’ll even maintain an inventory of heat-treated parts to further cut lead times. 

Request a quote today for your cost-effective, high-quality heat-treated parts.

Common Questions About Heat Treating 

What are the types of heat treatment? 

The most common types of heat treatment include annealing, normalizing, hardening, and tempering. Each process serves different purposes in modifying material properties.

What metals can be heat treated? 

Most metals can be heat-treated, although ferrous metals are the most commonly heat-treated materials.

Can aluminum be heat-treated? 

Certain aluminum alloys can be heat-treated, but pure aluminum cannot be heat-treated.

Can stainless steel be heat-treated? 

Yes, stainless steel can be heat treated, but the process is somewhat complex due to its chromium content. Different stainless steel grades respond differently to heat treatment.

What is the heat-treating process for CNC machined parts? 

The heat-treating process varies depending on the type of heat treatment chosen and the specifics of the part. In general, it typically involves careful temperature control and proper fixturing to minimize distortion.

Should machining be done before or after heat treatment? 

Both options are possible, and several key factors will dictate whether heat treating before or after machining is optimal for a given project. Heat treating after machining, for instance, allows easier and faster machining, but there is a greater risk of distortion during heat treatment. 

What are the disadvantages of heat treatment? 

Heat treatment can add to processing time, and there are risks of complications such as distortion.

How much does heat treating cost? 

Pricing is dependent on factors such as part size, material type, treatment type, and complexity. Ultimately, pricing will vary from vendor to vendor.